In image reconstruction based on Computed Tomography (CT) data, a CT image reconstruction system is required to have a high image reconstruction speed due to a requirement of real-time capability. The image reconstruction speed generally refers to the number of images reconstructed per second.
A pipelining technology is often employed in the CT image reconstruction. Multiple steps involved in the image reconstruction are executed in parallel as a pipeline. For example, several steps such as data reading, correction, back-projection and post-processing involved in the tomography image reconstruction are executed in parallel as a pipeline. In order to improve a system operating speed, respective execution units may also operate in a multi-thread mode. In general, the more the threads in one execution unit for implementing a task are, the shorter the time consumed for executing the task is. However, the number of threads executed in parallel in one execution unit is limited due to a limitation of hardware resources (such as a CPU, a memory and a graphics card).
In the conventional technologies, the numbers of threads in the execution units are generally configured beforehand for performing image reconstruction. However, since the CT system has different scanning and image-construction parameters and time needed for the execution of the image-construction execution units varies under different scanning and image-construction parameters, it is impossible to achieve fastest image reconstruction speed under different scanning and image-construction parameters with fixed number of threads configured beforehand.